BAGHDAD, Iraq (CNN) -- The State Department's initial report of last month's incident in which Blackwater guards were accused of killing Iraqi civilians was written by a Blackwater contractor working in the embassy security detail, according to government and industry sources.

In this September 24 photo, an Iraqi looks at a car that was destroyed during the September 16 incident.

A source involved in diplomatic security at the U.S. Embassy in Baghdad said a Blackwater contractor, Darren Hanner, drafted the two-page "spot report" on the letterhead of the Bureau of Diplomatic Security for the embassy's Tactical Operations Center.

That office -- which tracks and monitors all incidents and movements involving diplomatic security missions -- has outsourced positions to Blackwater and another private firm, the embassy source said.

A highly placed industry source said that Hanner, who was listed on the report as the TOC watch officer, was working for Blackwater at the time the report was written, just after the September 16 incident occurred. He was to rotate out of Iraq this past week, the source said.

The man who approved the report was Ricardo Colon, whom the embassy source identified as the embassy's deputy regional security officer. A State Department source confirmed a Ricardo Colon Cifredo works for the State Department in Iraq.

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The deadly incident produced an outcry in Iraq and raised questions about the accountability of foreign security contractors in Iraq, who, under an order laid down by the U.S.-led occupation government, are not subject to Iraqi law for actions taken within their contracts.

Anne Tyrrell, a spokeswoman for Blackwater, emphasized that the State Department is doing its own investigation into the incident.

The FBI is sending a team of agents to assist the U.S. investigation at the State Department's request, FBI spokesman Richard Kolko said Monday.

Blackwater -- which provides security to U.S. diplomats -- says its employees responded properly to an insurgent attack on a convoy. The State Department "spot report" underscores that scenario and doesn't mention civilian casualties.

However, those accounts are at odds with what the Iraqis are saying.

A senior Iraqi National Police official participating in the Iraqi governmental probe of the shooting said the Blackwater gunfire was unprovoked and the guards fired randomly, killing several civilians and wounding others. Watch Iraqi police video of the incident aftermath »

Tom Casey, deputy State Department spokesman, noted that a spot report "is a first-blush account of those on the scene" and that the "report has no standing whatsoever."

"It was not intended to be used as an analysis, investigation, review or any detailed assessment of the situation," Casey said. "To assert that (it is) is untrue," Casey said.

The embassy source said after the spot report was completed and approved, a State Department agent took sworn statements from the participants in the shooting.

The senior Iraqi police officer said that Blackwater team members were questioned by Iraqi police immediately after the incident and initially said they opened fire in response to a mortar attack. However, he said, they then changed their story at least twice during the 90 minutes they were held.

Erik Prince, the CEO of Blackwater, was to testify Tuesday before the House Oversight and Government Reform Committee.E-mail to a friend